A 16-year-old boy presents with headache and inability to look upwards. Examination shows impaired upgaze, convergence-retraction nystagmus, and light-near dissociation. MRI shows a pineal region mass. Serum AFP is normal and beta-hCG is normal. Which tumour is most likely, and what property makes it uniquely treatable?

• A Germinoma, exquisitely radiosensitive ✓
• B Pineoblastoma, cured by chemotherapy alone
• C Yolk sac tumour, cured by complete excision only
• D Choriocarcinoma, cured by surgical debulking alone

Explanation

The combination of upgaze palsy, convergence-retraction nystagmus and light-near dissociation is Parinaud syndrome, caused by compression of the tectal plate by a pineal region mass. Intracranial germinoma is the commonest pineal region germ cell tumour in adolescent males, secretes no significant markers when pure, and is extremely radiosensitive, so radiotherapy alone achieves high cure rates. Elevated AFP would point to a yolk sac component, and choriocarcinoma raises beta-hCG, which kills those distractors here.

Reference: Greenberg Handbook of Neurosurgery, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.